The invention relates to a portable power tool system comprising a portable power tool (12a-n), especially an angle grinder, a protective hood unit (14a-n) and a protective hood anti-rotation lock (16a-n) for providing anti-rotational locking between the protective hood unit (14a-n) and the portable power tool (12a-n) in the event of a breakage of a tool (18a-n). According to the invention, the protective hood anti-rotation lock (16a-n) is adapted to provide anti-rotational locking between the protective hood unit (14a-n) and the portable power tool (12a-n) while at the same time securing the protective hood unit (14a-n) to the portable power tool (12a-n) in a working position of the protective hood unit (14a-n).